Electric annunciator



(No Model.)

I. H. PARNHAM.

ELECTRIC ANNUNGIATOR.

No. 294,212. Patented Feb. 26, 1884.

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UNITED STATES PATENT OFFICE.

ISAIAH H. FARNHAM, OF PORTLAND, MAINE, ASSIGNOR TO THE AMERICAN BELLTELEPHONE COMPANY, OF MASSACHUSETTS.

ELECTRIC ANNUNClATOR.

SPECIFICATION forming part of Letters Patent No. 294,212, dated February26, 1884.

Application filed December 26, 1883. (X0 model.)

numbered 281,4;78, for Telephone System and Apparatus, I have; shown anddescribed the annunciator which forms the subject of my presentinvention, in connection with improved telephoneexchange appliances.

The object I have in view is to produce an annunciator of extremesimplicity and economy in construction. comprising but few componentparts, easy to be adjusted, and capable of fully responding to a veryweak callingcurrent of either direction. In this annunciator theadjustments are very simple, comprising only two movementsnamely, ato-and-fro movement of the electro-magnet, and also .a rotary movementof the electromagnet.

Figure 1 is a front elevation of the annunciator, and Fig. 2 a sectionalside elevation of the same.

The details of construction are as follows:

I A suitable case, A, is fitted with a glass front,

. similar suitable support.

B, and a short distance from the internal surface of the said glass asteel magnet, O, magnetized either permanently or by induction, isdelicately pivoted at a in a plate, b, of brass or other non-magneticmaterial, or in a Immediately behind t-he said support is an ordinaryelectromagnet, D, which, by means of an adjustingscrew, f, working in anut or threaded ring, 9, is capable of adjustment to and from theneedle, and also may be turned to any required degree on its axis, asshown in dotted lines in Fig. 1, which is a front elevation of Fig. 2.

- The spindle 0 of the adjusting-screw is rigidly attached to the yoke Zof the electro-magnet, and turns easily in the gland d, which is fittedin the recess is of the partition E and secured by the lock -nut e andset-screw s.

The threaded part of the spindle cis provided with a second lock-nut, g,and the head or handle f, in a manner well understood, may also bedetachable, for convenience in construction, and be screwed to thespindle. \Vhen the magnet is to be adj ustedforward or backward from theneedle, it is only necessary to loosen the lock-nut g, and then push orpull tromagnet, whereby it is enabled to act more or less powerfully onthe said needle.- This adjustment is accomplished by loosening thelock-nut g, and then turning the spindle c to the left or right, as maybe desired. The needle C may also be slightly weighted, if necessary, atits lower end but this will not usually be requisite, and I do notprefer it, as the sensitiveness of the annunciator is thereby impaired.The electromagnet D may be con nected with any electric circuit by meansof the wires h and 11.

One great advantage possessed by my annunciator over others used intelephony consists in the fact that it resumes its normal position assoon as the circuit is opened at the signal-sending point. It is,moreover, capable of responding differently to currents of eitherdirection, a current of given direction producing a deflection to theright, while a current of opposite direction produces a deflection tothe left.

Having now described my invention, I claim- An .annunciator consistingof an electromagnet capable of horizontal and rotary adjustment, andprovided with a magnetic and polarized needle pivoted in front of orbetween the poles of the electro-magnet, substantially as described.

In testimony whereof I have signed my name to this specification,in thepresence of two subscribing witnesses, this 2lst day of December, A. D.1883.

ISAIAH H. FARNHAM. Witnesses:

ARDON \V. OooMBs, FRANK S. Wirnnnoosn.

